Look on the Bright Side: Exploring the Role of Episodic Future Thinking in Anticipatory Anhedonia.

Abstract

Anhedonia, the diminished capacity to experience pleasure, is a debilitating symptom that impacts motivation, social engagement, and quality of life. While traditionally linked to psychiatric disorders, it is increasingly recognised as a key feature of frontotemporal dementia (FTD). This thesis investigates the multidimensional nature of anhedonia and its cognitive underpinnings across four studies.

Chapter 2 identifies distinct motivational profiles in dementia syndromes: global motivational impairment in behavioural variant FTD (bvFTD), a primarily anhedonic profile in semantic dementia (SD), and executive/apathy-related disturbances in Alzheimer’s disease (AD), with syndrome-specific links to functional decline. Chapter 3 further characterises anhedonia, revealing widespread impairments across anticipatory and consummatory dimensions in bvFTD and SD, while consummatory pleasure is relatively preserved in AD. Correlational findings highlight novel associations between anhedonia and everyday behavioural changes. Chapter 4 explores cognitive mechanisms, showing that deficits in episodic future thinking are associated with anticipatory anhedonia in FTD, suggesting an impaired ability to imagine positive future events. Chapter 5 compares anhedonia in bvFTD and mood disorders, demonstrating that consummatory anhedonia may distinguish neurodegenerative from affective conditions.

Together, the work presented in this thesis underscores the importance of recognising anhedonia as a core clinical feature of FTD, with significant implications for diagnosis, management, and quality of life. By elucidating the cognitive and behavioural underpinnings of anhedonia, this work paves the way for more targeted interventions aimed at improving patient outcomes and supporting caregivers.